SPITZER ULTRA FAINT SURVEY PROGRAM (SURFS UP). II. IRAC-DETECTED LYMAN-BREAK GALAXIES AT 6 z 10 BEHIND STRONG-LENSING CLUSTERS

• Published in: The Astrophysical journal Vol. 817; no. 1; pp. 11 - 32
• Main Authors: Huang, Kuang-Han, Brada, Maruša, Lemaux, Brian C., Ryan, Jr, R. E., Hoag, Austin, Castellano, Marco, Amorín, Ricardo, Fontana, Adriano, Brammer, Gabriel B., Cain, Benjamin, Lubin, L. M., Merlin, Emiliano, Schmidt, Kasper B., Schrabback, Tim, Treu, Tommaso, Gonzalez, Anthony H., Linden, Anja von der, Knight, Robert I.
• Format: Journal Article
• Language: English
• Published: United States The American Astronomical Society 20.01.2016
• Subjects: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COLOR; DATA ANALYSIS; DETECTION; EMISSION SPECTRA; GALAXIES; galaxies: evolution; galaxies: high-redshift; GALAXY CLUSTERS; GALAXY NUCLEI; GRAVITATIONAL LENSES; gravitational lensing: strong; MASS; methods: data analysis; RED SHIFT; SIGNAL-TO-NOISE RATIO; TELESCOPES
• DOI: 10.3847/0004-637X/817/1/11
• ISSN: 0004-637X

ABSTRACT We study the stellar population properties of the IRAC-detected 6 z 10 galaxy candidates from the Spitzer UltRa Faint SUrvey Program. Using the Lyman Break selection technique, we find a total of 17 galaxy candidates at 6 z 10 from Hubble Space Telescope images (including the full-depth images from the Hubble Frontier Fields program for MACS 1149 and MACS 0717) that have detections at signal-to-noise ratios ≥ 3 in at least one of the IRAC 3.6 and 4.5 m channels. According to the best mass models available for the surveyed galaxy clusters, these IRAC-detected galaxy candidates are magnified by factors of ∼1.2-5.5. Due to the magnification of the foreground galaxy clusters, the rest-frame UV absolute magnitudes M1600 are between −21.2 and −18.9 mag, while their intrinsic stellar masses are between 2 × 108M and 2.9 × 109M . We identify two Ly emitters in our sample from the Keck DEIMOS spectra, one at zLy = 6.76 (in RXJ 1347) and one at zLy = 6.32 (in MACS 0454). We find that 4 out of 17 z 6 galaxy candidates are favored by z 1 solutions when IRAC fluxes are included in photometric redshift fitting. We also show that IRAC [3.6]-[4.5] color, when combined with photometric redshift, can be used to identify galaxies which likely have strong nebular emission lines or obscured active galactic nucleus contributions within certain redshift windows.